The present invention relates to a process for the carbonylation of an acyl halide to form an .alpha.-keto-carboxylic acid as the product.
The practical value of such .alpha.-keto-carboxylic acids is that they can be used to prepare the corresponding .alpha.-amino-acids or .alpha.-hydroxy acids which play an important role in biochemistry. For example, Saegusa et al, Journal of Organic Chemistry, Vol. 42, No. 16, 2797-2798 (1977) teach the selective reduction of .alpha.-keto acids to .alpha.-hydroxy acids by the use of certain phosphites as reducing agents. And, Tachibana et al, Chemistry Letters, pp. 1765-1768 (1982) disclose the transformation of .alpha.-keto acids to the corresponding .alpha.-amino acids by the reaction with chiral pyridoxamine analog, (R)- or (S)-15-aminomethyl-14-hydroxy-5,5-dimethyl-2,8-dithia[9](2,5)pyridinophane (4), and Zn.sup.2+ in the molar ratio of 2:1, in methanol.
The preparation of .alpha.-keto-carboxylic acids and their derivatives has been the subject of a large number of investigations. According to Rodd, The Chemistry of Carbon Compounds (1952 edition), Vol. 1, pages 227-229, the following methods of preparation are available:
gentle oxidation of .alpha.-hydroxyacids containing a secondary hydroxyl group, or by the enzymatic deamination of .alpha.-amino-acids; PA0 hydrolysis of an acyl cyanide; PA0 hydrolysis of .alpha.-oximino-esters; PA0 from glycidic acid esters on treatment with benzene saturated with boron trifluoride; PA0 from .alpha.,.beta.-dibromocarboxylic acids by forming a piperidine addition compound followed by hydrolysis; PA0 from .alpha.-keto-acetals by ultraviolet irradiation in the presence of N-bromosuccinimide; PA0 from .alpha.-bromomethylketones by boiling with selenium dioxide in absolute methanol or ethanol; PA0 from carboxylic acid esters by oxidation with selenium dioxide; PA0 permanganate oxidation of vinyl ketones; PA0 from carboxylic acid esters by condensation with oxalic ester followed by decarboxylation; PA0 from aldehydes via 5-alkylidine-2-thio-oxazolid-4-ones or by reaction with methyl methoxyacetate; hydrolysis of azalactones or acetamido-acrylic acids; hydrolysis of the reaction product of Grignard reagents on diethyl-oxamic ester; PA0 oxidation of -hydroxyacid esters containing two .beta.-hydrogen atoms by N-bromosuccinimide in carbon tetrachloride to .beta.-bromo-.alpha.-keto-acid esters; and by the action of alpha on the dimethanesulphonates and ditoluene-p-sulphonates of .alpha.,.beta.-dihydroxycarboxylic acids. PA0 pyruvic acid, PA0 2-oxo-butanoic acid PA0 2-oxo-3-methylbutyric acid, PA0 2-oxo-dodecanoic acid, PA0 cyclohexylglyoxylic acid, PA0 2-oxo-hept-6-enoic acid, PA0 phenylpyruvic acid, PA0 p-tolylpyruvic acid, PA0 benzylpyruvic acid, PA0 2-chloro-2-oxopropinoic acid, PA0 p-chlorophenylpyruvic acid, and the like. PA0 acetyl chloride, PA0 acetyl bromide, PA0 propanoyl chloride, PA0 propanoyl bromide, PA0 isobutyryl chloride, PA0 isobutyryl bromide, PA0 undecanoyl chloride PA0 undecanoyl bromide, PA0 cyclohexanecarbonyl chloride, PA0 cyclohexanecarbonyl bromide, PA0 hex-5-enoylchloride, PA0 hex-5-enoylbromide, PA0 phenylacetyl chloride, PA0 phenylacetyl bromide, PA0 p-tolylacetyl chloride, PA0 p-tolylacetyl bromide, PA0 3-phenylpropanoyl chloride, PA0 3-phenylpropanoyl bromide, PA0 chloroacetyl chloride PA0 p-chlorophenylacetyl chloride, and the like.
In pending U.S. Ser. No. 353,473, entitled "Process for Preparing Alkyl Alpha-Keto-Carboxylic Acids from Alkyl Halides", filed on Mar. 1, 1982, there is disclosed a method of preparing an alkyl .alpha.-keto-carboxylic acid by reacting a primary alkyl halide in a liquid solvent medium with carbon monoxide at elevated temperature and elevated pressure in the presence of a catalytic amount of a metal carbonyl compound, such as dicobalt-octacarbonyl and an alkali metal base or an alkaline earth metal base.
Methods also are known for preparing arylpyruvic acids. For example, U.S. Pat. No. 4,152,352 discloses the preparation of an arylpyruvic acid by reacting an arylmethyl halide in a liquid solvent medium with carbon monoxide at pressures of 5 to 200 bars in the presence of a catalytic amount of a metal carbonyl compound and an alkaline earth metal inorganic base. Further, U.K. patent application No. 2,026,478A discloses that alkali metal salts of an arylpyruvic acid can be prepared by reacting an arylmethyl halide, carbon monoxide and an alkali metal base in the presence of a metal carbonyl compound as catalyst and in the presence of an alcohol or cyclic ether as solvent.
Finally, it is known in the art to react an acyl halide or alkyl halide in the presence of carbon monoxide, with a nucleophilic transition metal anionic complex to produce the corresponding acyl metal carbonyl derivative. See, for example, Heck, Organotransition Metal Chemistry, (Academic Press, New York, N.Y. 1974) pp. 200-209.